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Soy's Undeserved Bad Reputation

Sorting through the misinformation about soy

Dr. Padma Garvey

Soy’s Undeserved Bad Reputation

Tofu was first made from soy beans two thousand years ago as a source of protein for Buddhist monks.  It has been consumed widely and regularly throughout Southeast Asia for centuries.  Prior to the 1950s, the diets of most Southeast Asians were largely plant-based.  The quantity of animal protein consumed was much lower prior to the 1950s than in recent years.  In addition, prior to 1950, dairy consumption was rare in Southeast Asia, as was processed food consumption.  Over the course of the past 50 years, there have been significant changes to the eating patterns of many people throughout Southeast Asia.  Globalization and the introduction of Western style foods has led to an increase in the rates of heart disease, obesity, diabetes and cancer.  Recently China has set a goal to reduce meat consumption in the country by 2030 in order to curb greenhouse gas emissions.  The German government has recently banned meat and fish at all official government functions in accordance with their plan to deal with global warming.  If we take global warming seriously, then we need to encourage people to eat healthy plant-based foods, soy being one of them.

One of the things soy is blamed for is thyroid cancer.  All over the world, the incidence of thyroid cancer is rising.  It is especially high in South Korea.  Thyroid cancer is rarely fatal.  In the old days, before ultrasounds were so readily available, thyroid cancer was diagnosed after a nodule felt by the doctor grew over time.  Nowadays, we are able to pick up the smallest dot of thyroid cancer because of excessive use of ultrasounds and end up over treating lots of people whose dot of thyroid cancer would never have killed them in the first place.  Thyroid cancers tend to occur in areas with iodine deficiencies.  In addition, the thyroid is sensitive to radiation exposure, even at low levels.  Low levels of radiation exposure will affect fetal thyroid tissue as well.  The effects of the two atomic bombs exploded on Japan in 1945, were seen in subsequent generations.  Since then there have been significant events in Chernobyl and Fukishima.  About twenty years ago, South Korea started an intensive screening program for thyroid cancer leading to the huge increase in diagnoses and treatments but with no change in the already extremely low rates of death from thyroid cancers.  Interestingly, South Korea is reexamining the usefulness of such an aggressive screening program.  The rising rates of thyroid cancers are occurring as soy consumption has decreased in areas like South Korea, as a once plant-based diet has been replaced with higher meat and dairy consumption.


Because of reports that soy contains chemicals called phytoestrogens, many healthcare providers have erroneously told patients that they should avoid soy because it may cause breast cancer.   This is not based on any proven scientific data.  In fact, around the world, countries with the highest rates of soy consumption have lower rates of breast cancer.  Countries consuming more meat and animal dairy consistently have more breast cancer.  Okinawans, one of the healthiest groups on earth, eat more soy than any other group, averaging 2 servings a day.   

As of 2015, there are only a handful of genetically-modified crops in the market: rice, corn, seed oil, and soy bean.  It is important to avoid GMO foods as a way to minimize pesticide exposure.  Luckily there are many GMO-free soy foods readily available.  Make sure you see the GMO-free label on soy foods you buy.  Soy beans are used to make processed foods like meat substitutes.  Commercially available soy burgers and soy hot dogs are processed foods and should be avoided like any processed food.

Based on all this information, I think the magnificent, versatile, wholesome soy bean has gotten a really bad deal.  As always you should stick to unprocessed food.  Opt for GMO-free soy beans.  If you like tofu, soy milk, miso, and tempeh but are afraid to eat them, don’t be.  Enjoy your soy.


Other articles by Padma Garvey